Study Material
KINEMATIC THEORY
Very Short Answer Questions
Q1. Define mean free path.
Answer
Ans. The average distance an atom or a molecule can travel without colliding is called mean free path.
Q2. How does kinetic theory justify Avogadro's hypothesis and show than Avogadro Number in different gases is same?
Answer
Ans. })
When pressure (P), volume (V) and temperature (T) remains same, the number of molecules N= constant. Hence, “equal volumes of all gases under similar conditions of temperature and pressure have the same number of molecules”. This is Avogadro’s hypothesis. kinetic theory justify Avogadro’s hypothesis.
Q3. When does a real gas behave like an
Answer
Ans. At low pressures and high temperatures real gases behave like an ideal gases.
Q4. State Boyle's Law and Charles Law ideal gas?
Answer
Ans. Boyle’s law: At constant temperature, the volume (v) of a given mass of a gas is inversely proportional to its pressure (P).
Charles law: At constant pressure, the volume (v) of a given mass of a gas is directly proportional to its absolute temperature (T).
Q5. State Dalton's law of partial pressures
Answer
Ans. The total pressure of mixture of ideal gases is equal to the sum of the partial pressures of individual gases present in the mixture.
Total pressure (P)= P1+P2+P3+...
Q6. Pressure of an ideal gas in container is independent of shape of the container-explain
Answer
Ans. P= ⅓ mnV2 The pressure depends on the mass of the gas, number of molecules in the gas and the rms velocity of the molecules. The pressure is independent of its area and volume.So pressure of an ideal gas in a container is independent of the shape of the container.
Q7. Explain the concept of degrees of freedom for molecules of a gas.
Answer
Ans. The number of degrees of freedom of a dynamical system is defined as the total number of coordinates or independent quantities to describe completely the position and configuration of the system
Q8. What is the expression between pressure and kinetic energy of a gas molecule?
Answer
Ans. 𝑃𝑉 =⅔𝐸 (p = pressure, v= volume, E= kinetic energy)
Q9. The absolute temperature of a gas is incresed 3 times. What will be the increase in rms velocity of the gas molecule?:
Answer
Ans. 
Q1. Explain the kinetic interpretation of Temperature
Q2. How specific heat capacity of mono atomic, diatomic and poly atomic gases can be explained on the basis of Law of equipartition of Energy?
Q3. Explain the concept of absolute zero of temperature on the basis of kinetic theory.
Q4. Prove that the average kinetic energy of a molecule of an ideal gas is directly proportinal to the absolute temperature of the gas.
Q5. Two thermally insulated vessels 1 and 2 of volumes V, and V are joined with a valve and filled with air at temperatures (T,. T) and presures (PP) reaspectively. If the valve joining the two vessels is opened, what will be the temperture inside the vessels at equilibrium.
Q6. What is the ratio of r.m.s speed of Oxygen and Hydrogen molecules at the same temperature?
Q7. Four molecules of a gas have speeds 1,2,3 and 4 km/s.Find the rms speed of the molecule.
Q8. If a gas has 'T degrees of freedom, find the ratio of C and C
Q9. Calculate the molecular K.E of 1 gram of Helium (Molecular weight 4) at 127°C. Given R 8.31 J mol K
Q10. When pressure increases by 2 %, what is the percentage decrease in the volume of a gas, assuming Boyle's law is obeyed?
Q1. Derive an expression for the Pressure of an ideal gas in a container from Kinetic Theory and hence give Kinetic Interpretation of Temperature.